A Heterolepidoderma and Halichaetoderma gen. nov. (Gastrotricha: Chaetonotidae) riddle: integrative taxonomy and phylogeny of six new freshwater species from Central Europe
Author:
Rataj Križanová Františka1ORCID,
Vďačný Peter1
Affiliation:
1. Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava , 842 15 Bratislava , Slovakia
Abstract
Abstract
Heterolepidoderma is a widely distributed gastrotrich genus encompassing 22 freshwater and 15 marine species. In the present study, two new Heterolepidoderma and four new Heterolepidoderma-like species were discovered in the inland waters of Central Europe. Although Heterolepidoderma-like species exhibited all the morphological features typical of Heterolepidoderma, both nuclear and mitochondrial genes robustly showed their sister-group relationship to the marine genus Halichaetonotus. Most Heterolepidoderma species, including the new ones, were grouped with some Chaetonotus and Ichthydium species in a strongly supported cluster (so-called Heterolepidoderma s.l. clade). Since statistical tree topology tests robustly refuted the close affinity of Heterolepidoderma-like species to the Heterolepidoderma s.l. clade, a new genus, Halichaetoderma gen. nov., was proposed for them. Stochastic mapping suggested that the last common ancestor (LCA) of the Chaetonotidae‒Neogosseidae‒Dasydytidae clade had scales carrying keels with spines. Scales became oblong in the LCA of the Halichaetoderma + Halichaetonotus clade and three times independently within the Heterolepidoderma s.l. clade. Spines were lost in the LCAs of the Halichaetoderma + Halichaetonotus and Heterolepidoderma s.l. clades convergently. State-by-state associations of cuticular characters suggested that particular scale morphologies tend to be correlated with particular numbers of keels and the presence/absence of spines during the chaetonotid phylogeny.
Funder
Slovak Research and Development Agency
Ministry of Education, Science, Research and Sport of the Slovak Republic and Slovak Academy of Sciences
Publisher
Oxford University Press (OUP)
Subject
Animal Science and Zoology,Ecology, Evolution, Behavior and Systematics
Reference71 articles.
1. Prime ricerche sui Gastrotrichi dulciacquicoli Italiani;Balsamo;Atti della Società Toscana di Scienze Naturali Memorie, Serie B,1978
2. Gastrotrichs from interstitial fresh water, with a description of four new species;Balsamo;Hydrobiologia,1995
3. Global diversity of gastrotrichs (Gastrotricha) in freshwaters;Balsamo;Hydrobiologia,2008
4. Gastrotricha. Biology, ecology and systematics. Families Dasydytidae, Dichaeturidae, Neogosseidae, Proichthydiidae;Balsamo,2014
5. SIMMAP: stochastic character mapping of discrete traits on phylogenies;Bollback;BMC Bioinformatics,2006